Magnetostrictive apparatus for cleaning sheet material



g- 1955 J. w. MCAULEY ETAL 3,198,971

MAGNETOSTRICTIVE APPARATUS FOR CLEANING SHEET MATERIAL Original Filed May 17, 1957 3 Sheets-Sheet 1 T n iiwg Q? 204% f z wvfie ATTORNEY 3, 1965 J. w. M AULEY EI'AL 3,198,971

MAGNETOSTRICTIVE APPARATUS FOR CLEANING SHEET MATERIAL Original Filed May 17, 1957 S Sheets-Sheet 2 INVENTORS 51 may WFQMFI/ M /aezwmflfi awn A TTORN E YS 3, 1955 J. w. MCAULEY EIAL 3,198,971

MAGNETOSTRICTIVE APPARATUS FOR CLEANING SHEET MATERIAL Original Filed May 17, 1957 3 Sheets-Sheet 3 @666 f if (Jo/1e ATTORNEYS United States Patent 3,193,971 MAGNETGSTRECTHVE APPARATUS FOR CLEAN- ENG SI'ILFE'I MATERIAL James W. NcAuley and Wiliiam E. McCown, Toledo,

Uhio, assignors to Lihhey=Gwens-Ford Glass Company, Toledo, @hie, a corporation of Ohio Original appiication May 17, 1957, Ser. No. 659,934 new Patent No. 2,981,268, dated Apr. 25, 1961. Divided and this application Apr. 10, 1959, Ser. No. 805,609

3 Claims. (Cl. 310-26) The present invention relates broadly to sonic vibration generating apparatus, and in particular to an improved form of surface treating apparatus that employs sonic vibrations.

This application is a division of our copending application Serial No. 659,934, filed May 17, 1957 now Patent No. 2,981,268.

Although the invention is not restricted to the treating of any particular surface, whether of glass or any other material, it is especially well adapted to carry out the diiiicult job of cleaning glass sheets, particularly plate glass sheets which have been bedded in plaster of Paris during a prior grinding and polishing operation or sheets which are covered with a layer of polishing rouge. Heretofore, the removal of this plaster and rouge, and other foreign matter from the surface of glass sheets was difficult to achieve.

Now, however, by means of the present invention even this diificult and unusual cleaning operation can be carried out without the deficiencies and objectionable features of previous cleaning methods, by the use of sonic vibrations, preferably in the frequency range between 100 and 30,000 cycles per second which are transmitted in the form of vibration sound waves through a suitable medium in contact with the surface to be cleaned. As these sound waves are propagated throughthe medium which for our purpose is a liquid, motion of the particles of the liquid will produce an alternate formation and collapse of gas bubbles, which phenomenon is referred to as cavitation. The collapse of the bubbles creates an agitation of sufiicient magnitude within the medium to disintegrate particles of substantially solid materials which are in contact with the medium.

In its more specific aspects, the present invention employs the phenomenon just described to wash the underside of a glass sheet by passing the sheet through a bath of suitable liquid medium which is being vibrated by sonic energy generating elements. These generating elements which may be magnetostrictive transducers of a conventional construction utilizing a core made up of a stack of thin laminated leaves or strips of ferromagnetic material, a coil connected to a suitable power source and a magnet for providing a polarized effect on the core and are preferably arranged so as to direct the generated energy onto the glass sheets being moved thereover along a path substantially normal to the surface thereof.

Heretofore, it has been difficult to clean the underside of a glass sheet by sonic methods without turning the sheets over. This turning of relatively large glass sheets is not only a difiicult and time consuming job, but also one in which the risk of chipping, scratching, and breaking of the sheets is very great.

It is therefore an object of this invention to provide a novel apparatus for thoroughly cleaning the lower surface of sheet material in a continuous manner, and one that is particularly suited for use in a factory production line.

Still another object of the invention is the provision of a magnetostrictive transducer core constructed in a novel manner having the laminated leaves clamped together to prevent lateral movement therebe'tween.

the sheet surface.

3,198,971 Patented Aug. 3, 1965 ice Another object is the provision of a power factor correctig means and the vibration generating means as a unitary structure.

In the drawings wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a fragmentary plan view of a cleaning section of a production line, showing cleaning apparatus constructed in accordance with the invention incorporated herein;

FIG. 2 is a longitudinal section taken substantially along line 22 of FIG. 1;

FIG. 3 is a fragmentary vertical sectional view taken along 3--'3 of FIG. 2;

FIG. 4 is a fragmentary plan view of a transducer in position in the cleaning apparatus according to a preferred embodiment of the invention;

FIG. 5 is a vertical sectional view through a transducer housing and mounting taken along line 5-5 of FIG. 4;

FIG. 6 is a cross-sectional view of a transducer core and coil taken along 66 of FIG. 5;

FIG. 7 is a cross-sectional view through a transducer core and magnet taken along line 77 of FIG. 5;

FIG. 8 is a vertical cross-sectional view taken along line 8-3 of FIG. 6;

FIG. 9 is a longitudinal plan View partially in section of a modified form of the invention;

FIG. 10 is a perspective view of a clamping bar for use in the modified form of the invention;

FIG. 11 is a sectional view of atransducer in operating position according to the modified form of the invention;

FIG. 12 is a sealing gasket for use in the modified form of the invention; and

FIG. 1-3 is a perspective view of the core lamination retaining clip of FIG. 5.

With a more detailed reference to the drawings, and particularly to FIG. 1, there is shown the cleaning section of a grinding and polishing line. Ordinarily a glass sheet after being polished on one side is turned over bedded in plaster and sent back through the polishing apparatus in order to polish the other side. On emerging from the polishing apparatus after this second polishing operation, the undersurface of the glass sheet must be cleaned to remove any plaster or other foreign material which may have been picked up during the polishing of the opposite side. Heretofore, in order to clean this underside of the glass sheet by sonic means it was customa-ry to turn the underside upward before cleaning. It is obvious that cleaning the underside of a glass sheet in this manner is not only difficult from a handling standpoint, but is also time consuming and therefore objectionable for a production line in which large numbers of glass sheets are to be processed in a relatively short time.

Briefly to remove foreign material from the underside of sheet material according to the invention there are provided a plurality of vibration generating elements, magnetostrictive transducers for example, mounted in a unique fashion beneath the sheet material to be cleaned. Between the sheet material and the working faces of the vibration generating elements there must of course be provided a suitable vibration transmitting material in contact with both the working faces of the transducer and The purpose of this energy transmitting material is to provide a medium in which the generated sonic vibrations may produce cavitation with the resultant agitation of the medium that loosens any foreign material that may be adhering to the surface being treated and thus permit these foreign particles to be easily removed. By mounting the transducers below the surface it is possible to clean the surface by sonic methods as the glass is passing through a bath of the energy transmitting material.

An additional advantage is to be gained by mounting the sonic generating elements beneath the glass sheet to be cleaned in that a constant distance between the surface to be cleaned and the generating elements is maintained. In apparatus where the transducers are mounted above the sheet an increase in the thickness of the sheet beyond a certain amount causes the sheet to strike the vibrating faces of the transducers. Obviously with the sheet material being carried above the generating elements in accordance with the invention any variation in the thickness of the sheet material will not produce this difiiculty.

Referring now to FIGS. 1, 2 and 3 in greater detail there is shown a portion of a cleaning section in which the lower surface of glass sheets are cleaned according to a preferred embodiment of the invention. This cleaning section includes a series of horizontally disposed rolls 2!) suitably journalled in support members 21 so that the upper peripheral surfaces of these rolls will provide a continuous planar conveying means for carrying a glass sheet 22 along a predetermined path. Spaced along the path of movement of the glass sheet 22 and adjustably secured to the support means 21 are guide rollers 23 which are disposed with their peripheral surfaces facing inwardly towards the glass sheet in order to receive the edges of the sheet and provide a guiding means for maintaining the sheet in a proper lateral position on the drive rolls. These rollers may be adjusted inwardly or outwardly in relation to the edge of the glass sheet for positioning the sheet accordingly, by loosening bolt 24, moving the roller arm 25 in the desired direction and then resecuring the bolt, as shown in FIG. 3.

In a preferred embodiment the vibration generating elements or transducers 26 are mounted individually in two lines substantially transverse to the path of movement of the sheet material and as is shown generally at 27 in FIG. 1. The working faces 28 of the transducers in each of the lines may be disposed so as to have their greatest width a at right angles to the path of movement of the sheet material, which arrangement provides a greater cleaning width of the line of elements. Also the two lines of transducers are staggered so that the transducers of one line will clean or treat the strips of the sheet material which have been left untreated by the spaces between the transducers of the other line. The rolls 20 and the upper portions 29 of the transducers are situated in a tank 30 filled with an energy transmitting medium 31 which for our purpose is preferably a liquid such as water. As can be seen best in FIG. 2 the lines 27 of transducers are mounted on raised portions 32 of the bottom of the tub 30 and in such a manner that each of these transducers presents its working face 28 parallel to the underside of the sheet 22 being conveyed thereover by rolls 20.

The spacing between the working face of the transducers and the surface of the glass to be cleaned has been found to produce the best results when it is in the order of .060-.100 of an inch. This spacing may be varied by loosening bolts 33 and positioning journal bracket 34 as necessary. Raising or lowering this bracket produces a corresponding change of position of rolls 20 and the glass sheet 22 carried thereon.

It is advisable in mounting these transducers in operative position to insure that the transducers are maintained securely. This is important since not only would a loose mounting of the transducer result in reduced efficiency of operation and an undesirable increase in operation noise because of vibration between the tub and transducer, but also since the working faces and upper portions 29 of the transducers are submerged in water any looseness in mounting would permit water to seep down to the electrical portions of the transducer outside the cleaning tub and increase the possibility of damaging it through short circuits.

Therefore, in mounting a transducer 26 of the type shown in FIG. 5 there is provided in the tank bottom 3%) for each transducer an opening 35 of suffiicient size to enable it to receive the lower portion 36 of a transducer. There are also provided support blocks 37 containing an opening of the same diameter as opening 35. These blocks are afiixed to the tub bottom 30 so that the opening 35 in the tank and the one in the block 37 are aligned. The transducer 26 is provided with an enlarged mounting plate 38 near its mid-point the diameter of which is slightly larger than the opening 35. Therefore when the lower or driving half of transducer 26 is lowered into position through the opening 3-5 and the aligned opening in the block, the mounting plate 38 rests on a gasket 39 interposed between the block and the mounting plate. The mounting plate 38 is held in a tight sealing relationship to the gasket by means of a pair of retaining clips 40 which engage the upper marginal edge of mounting plate 38. These clips 40 are provided with centrally located bolts 41 which when threaded into support blocks 37 force the mounting plate 38 down onto the gasket thus producing a tight waterproof seal. There is also provided locator keys 42 secured on block 37 by screws 43 which are adapted to engage notches 44 formed in the peripheral edge of the mounting plate 38. The notches 44 are diametrically located in the plate and more particularly are axially aligned with the greatest width a of the transducer working face 28 to assure that the transducers will be properly positioned in relation to one another.

As seen best in FIG. 5, the transducers which generate the sonic energy used in the cleaning process comprise a U-shaped core 4-5 which is a stack of thin laminated leaves or strips of ferromagnetic material; a coil 46 arranged in surrounding relationship to the legs of the core and which when connected to a power source of alternating current sets up an alternating magnetic field within the core; a magnet 47 positioned between the legs of the core for providing a polarizing effect on the core; an acoustical horn 48 firmly secured to the cross leg of the core for directing the vibratory energy produced by the magnetostrictive movement of the core to a region where this energy may be utilized.

Briefly, the principle of operation of a magnetostrictive transducer is that when an alternating current flows in the coil a corresponding alternating field is induced in the core which because of its inherent ferromagnetic properties produces a cyclic change in length of the core of the same frequency as that of the voltage which is used to energize. Since the acoustical horn 43 which is firmly fixed to one end of the core moves correspondingly with each cyclic change in length of the core, the free end of the horn or working face 28 serves as a useful source of vibratory energy. The frequency of the voltage used, for the purpose described herein is in the order of 10 kilocycles, although a number of satisfactory values may be found depending on the type of operation being performed, the amount of power used, and the particular design of transducer being used.

As shown in FIG. 5, the transducer has a protective cover 49 which encloses the lower portion 36 of the transducer including the core 45, coil 46, and magnet 47. This protective cover has projections 50 and 51 (FIGURES 6, 7 and 5 respectively) which are so disposed that when the cover is in position, the projections will hold or maintain the coil 46 and polarizing magnet 47, respectively in a fixed position. The projections 50 for holding the coil in place on the leg portions of the core are shown as four triangular portions in FIGS. 6 and 7, and the central projection 51 that holds the magnet in place is shown in FIG. 7.

With reference particularly to FIG. 8, there is disclosed the electrical components and connections thereto of a transducer as according to the preferred embodiment. The connection to the external supply of electrical power (not shown) is provided by jack plugs 52 disposed in the lower portion 53 of the cover 4-9. The use of jack plugs for making the electrical connections permits rapid and foolproof changing of transducers in case they fail or need repairs. Also shown is a condenser 54 provided for power factor correction.

In an alternate embodiment of the invention a plurality of transducers are arranged as is shown in FIG. 9 into a cleaning unit or module 55. These transducers are arranged in a spaced linear relationship, thus presenting a row of vibrating surfaces to be cleaned.

The transducers in this alternate embodiment are held in a fixed relationship with respect to a pair of module mounting irons 56 by means of a pair of unique securing bars 57. This securing bar 57 comprises an upper flange portion 58 which is so shaped as to fit over the flanges 58' of the transducers as in FIG. 11, and a serrated spacing portion 59 which when placed in position along the long side of a line of transducers in a module 55, the serrations 60 dovetail with the spaces between flanges of adjacent transducers. The effect achieved when the pair of securing bars 57 are in place is to provide a module in which individual transducers are secured in an immovable fixed relationship with each other and in which this relationship will not be changed by operational vibration in normal use.

As is shown in FIG. 11 there is provided a protective cover 61 which completely encloses the cores and coils of the transducer in a cleaning module 55. This cover is secured to mounting irons 56 by means of screws 62 threaded therein. Also provided on the inner sides of the cover 61 are longitudinally extending brackets 63 for holding the coils 46 on the legs of the cores 45 and another longitudinally extending bracket 64 for holding the magnets 47 in place between the core legs.

As in the preferred embodiment, electrical connections are made by means of jack plugs 65 in the lower side of the covers 49. By properly connecting the coils of the individual transducers only one set of jack plugs is needed for each module.

The mounting of a module in operative position is best illustrated in FIG. 11. The wall 66 of the tube is provided with an opening just large enough to receive the cover 61 of the module. The edges 67 of the opening are recessed in order to receive a gasket on which the overlapping edges of the securing bars 57 rest. The module 55 is then held against the tube Wall 66 by means of retaining plates 68 overlapping the bars 57 and secured by means of bolts 69 threaded into the wall.

In order to properly seal or make water tight a module 55 it is desirable to provide an additional specially shaped gasket 70 which is placed between the individual transducers. Such a gasket 70 is shown in FIG. 12. This gasket is so shaped as to be able to fit in the space 71 between the individual transducers (FIG. 9). The corner notches 72 are provided for fitting underneath the upper flange 58 of the securing bars 57 in order that these bars may hold the gaskets in place. The gaskets are of suitable thickness so that in a completed module 55 the spaces 71 between the individual transducers are filled and provide water-tight seal.

In the conventional construction of a magnetostrictve transducer core the laminated leaves or strips of ferromagnetic material are bound together with an adhesive material. It has been found that under service conditions the forces and heat to which the core of the transducer are subjected result in a separation of the laminations, thereby permitting them to vibrate and move laterally relative to each other. This has an adverse effect on the efllciency of the unit.

In accordance with another aspect of the present invention the aforementioned difficulty is overcome in a simple and inexpensive manner by mechanically clamping the laminations of the core together in face-to-face contacting relationship. In general, this is accomplished by a clamping means fitting around the laminations of each leg of the core so as to engage the outermost laminations and urge the laminations together into pressing face-to-face relationship which prevents the objectionable lateral movement of the leaves relative to each other eliminating any gapping between these laminations and thereby promoting more efficient operation of the transducer.

In FIG. 13 there is illustrated a unique core lamination retaining clip 73 which is snapped in place over the outer edges of the legs of the cores 45 as shown in FIGS. 5 and 11. These clips are made of a material such as spring steel for holding the laminations of the core in a close contacting or pinching relationship. The use of the clips eliminates any gapping between the laminations and thereby promotes a more eflicient operation.

It is to be understood that the forms of the invention disclosed herein are to be taken as the preferred embodiments thereof, and that various changes in the shape, size and arrangement of parts as well as various procedural changes may be resorted to without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. In apparatus for cleaning sheet material by sonic means, a plurality of magnetostrictvie transducers arranged side-by-side in spaced relation, each having a body portion and a mounting flange, a mounting surface provided with openings for receiving the body portions of the transducers therethrough, a first clamping means carried by said surface and engaging said flanges, and a sec- 0nd clamping means also carried by said surface and engaging the flanges of adjacent transducers to maintain them in fixed spaced relation.

2. In apparatus for cleaning sheet material by sonic means, a magnetostrictive transducer comprising a core formed of a plurality of relatively thin laminations, an acoustical horn secured to the laminations at one end of the core, and means for clamping the opposite free ends of the laminations together in face-to-face contacting relationship.

3. In apparatus for cleaning sheet material by sonic means, comprising a substantially U-shaped core including spaced substantially parallel legs and a base portion connecting said legs at one end, said core being formed of a plurality of relatively thin laminations, an acoustical horn secured to the base portion of the core, and means fitting around the laminations of each leg of the core and engaging the outermost laminations for urging the laminations together to maintain them in face-to-face contacting relationship.

References Cited by the Examiner UNITED STATES PATENTS 1,812,748 6/31 Kayser 310-217 1,820,531 8/31 Englehardt 310-217 X 2,116,522 5/38 Kunze 310-26 2,170,206 8/39 Mason 310-26 X 2,636,998 4/53 Davis et al. 310-26 2,784,119 3/57 McCown et al. 134-1 2,842,067 7/58 Stevens 310-26 2,864,592 12/58 Camp 310-26 2,890,354 6/59 McCoWn et al 310-26 MILTON O. HIRSHFIELD, Primary Examiner.

ORIS L. RADER, Examiner.

UNITED STATES PATENT OFFICE r CERTIFICATE OF CORRECTION Patent No. 3,198,971 August 3, 1965 James W. McAuley et al.

It is hereby certified that error appears in the above numbered pat-- ent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 68, after "duction line." insert the following paragraph:

Another object of the invention is the Hroyisin of an improved apparatus with which the underside of sheet materials can be cleaned by means of sonic vibrations column 2, line 1, beginning with "Another object" strike out all to and including "structure." in line 3, same column 2.

Signed and sealed this 15th day of February 1966.

EAL) est: 3 NEST W. SWIDER EDWARD J. BRENNER eating Officer Commissioner of Patents k 

2. IN APPARATUS FOR CLEANING SHEET MATERIAL BY SONIC MEANS, A MAGNETOSTRICTIVE TRANSDUCER COMPRISING A CORE FORMED OF A PLURALITY OF RELATIVELY THIN LAMINATIONS, AN ACOUSTICAL HORN SECURED TO THE LAMINATIONS AT ONE END OF THE CORE, AND MEANS FOR CLAMPING THE OPPOSITE FREE ENDS OF THE LAMINATIONS TOGETHER IN FACE-TO-FACE CONTACTING RELATIONSHIP. 